1. Field of the Invention
The present invention relates to a medical diagnostic imaging device.
2. Description of the Prior Art
In medical diagnostic imaging devices, such as computed or magnetic resonance tomography devices, an area of an examination subject to be imaged is positioned in an imaging volume of the diagnostic device for preparing images of this area. Particularly in magnetic resonance tomography devices, wherein, apart from a pickup opening, the imaging volume is frequently surrounded by a closed housing within the examination space, the positioning ensues with the aid of a support device that can be moved in at least one direction and on which the examination subject is borne. A projector which projects an optical marker onto the examination subject can be situated in the area of the pickup opening. In an initial moving process of the support device, the support device including the patient borne thereon is initially controlled such that the optical marker marks a center of the area to be imaged on the surface of the patient. A remaining moving path of the support device in the imaging volume results from the known distance of the optical marker from the imaging volume. For fixing the center of the area to be imaged, often the support device must be moved back and forth until the optical marker meets the desired center. Since the support device also exhibits a comparatively low moving speed, the aforementioned positioning is comparatively time-consuming. U.S. Pat. No. 4,117,337 describes a comparable positioning device for a computed tomography device.
In contrast to the aforementioned positioning, German OS 195 08 715 describes a method and a device for positioning a patient in an imaging medical diagnostic device with which the positioning is more reliable and faster. For this purpose, the area to be imaged is marked with a marker fixed onto the patient. An image pickup device, such as a video camera, acquires the marker fixed onto the patient in an image outside of the examination space. An imaging processing unit recognizes the marker in the image and determines its spatial position. A control device determines the moving path of the support device from the spatial position of the marker and the known position of the imaging volume, and controls a movement of the bearing device along the aforementioned moving path.
A particular disadvantage of the aforementioned device is that a complicated and expensive system containing an image pickup device and an image processing unit with corresponding software is utilized for determining the position of the marker. Furthermore, it is possible that the marker will adhere differently as a result of different surface conditions of garments or on the skin of the patient, so that the marker may become displaced. Moreover, many patients consider attachment of the marker as being unpleasant, particularly on the face.
U.S. Pat. No. 5,309,913 discloses a support device that is independent of an image-generating medical diagnostic device, this support device including a detection device for acquiring the position of a pointer device for navigating within diagnostic image data sets, particularly for supporting a stereotactic brain operation. The diagnostic image data sets, earlier in time, are generated with a medical diagnostic imaging device.
An object of the present invention is to provide a medical diagnostic imaging device that allows fast positioning of the examination subject and reduces the aforementioned disadvantages of known devices.
This object is inventively achieved in a medical diagnostic imaging device having a support device, which, for positioning a fixable area of an examination subject to be imaged in an imaging volume of the device, is fashioned for moving the examination subject thereon in at least one moving direction, a control device, which controls the movement of the support device, a pointer device, which, for prescribing the area to be imaged, points to the area to be imaged, and a detection device, which acquires the spatial position of the pointer device at least in the moving direction and which is connected to the control device for positioning the area to be imaged that is prescribed by the pointer device.
The area to be imaged can be simply and intuitively fixed by a person who is part of the diagnostic process who touches, for example, a corresponding point of the area to be imaged at a surface of the examination subject, with the pointer device. The spatial position of the pointer device can be detected by means of the detection device. A moving path of the bearing device, for positioning the area to be imaged in the imaging volume, can be detected from the spatial position of the pointer device and from a known initial position of the support device. In an initial moving process, the aforementioned moving path is traversed without interruptions. Thus, the time-intensive positioning process described above employing of an optical projection. Furthermore, a marker need not be attached onto the examination subject for fixing the area to be imaged. Moreover, the pointer and detection device are comparatively simple and therefore can be economically fashioned compared to image pickup device having an image processing unit and corresponding image recognition software.
In an embodiment, the pointer device is fashioned so as to be free of a fixed connection to the other device. A high degree of operating comfort is achieved for the person carrying out the diagnosis, particularly in an embodiment wherein the pointer is a hand-held device that is not mechanically connected to the diagnostic device.
In another embodiment, the detection device is disposed at a known distance from a part of the imaging device that cannot be moved. It is thereby achieved that the spatial position of the pointer device detected by the detection device exhibits a fixed reference to the diagnostic device.
In another embodiment, the pointer device and the detection device are fashioned such that the detection device can detect the spatial position as well as the orientation of the pointer device. For example, a center of the area to be imaged can be fixed more accurately as a result, particularly when the center within an examination subject is to be prescribed for all three spatial directions.
In a further embodiment, the pointer device and the detection device are fashioned such that the detection device can optically detect the spatial position and, if necessary, potentially the orientation of the pointer device. For example, U.S. Pat. Nos. 5,828,770 and 5,923,417 describe an embodiment for optical detection for this purpose. Optical detection ensures a reliable detection even in an environment with severe electromagnetic interference, as is present of a magnetic resonance tomography device, for example.
For this purpose, the detection device is a stereoscopic camera in an advantageous embodiment.
In another embodiment, the medical diagnostic imaging device is a computed or magnetic resonance tomography device. Particularly computed and magnetic resonance tomography devices represent medical diagnostic devices with a considerable original cost, so that a high utilization rate (throughout) is desired for such devices. The throughput is increased by reducing the examination time per patient, for example. When the area to be imaged is fixed in a simple, intuitive and fast manner, the positioning process per patient is reduced by approximately half a minute up to a full minute, so that approximately one to two more patients can be additionally examined per day, so that the patient throughput is increased. As used herein, xe2x80x9ccomputed tomography devicexe2x80x9d includes X-ray and electron beam computed tomography devices, as well as positron emission tomography devices.